Ratteling engine noise GSX 1100 1981 only then cold

[kz]

Hi,

Bike is GSX1100 1981

I (my brother) have a rattling noise in the engine when it is cold, the bike has behaved like that for 4 years, I have also asked this question here before but now some more checks are done.

The engine rattles badly then cold, runs perfect then warm.

We have checked:

Cam chain, cam tensioner, starter clutch, clutch and valves.

I have been told that it could be the crankshaft axial-bearings that make the crank moving in axial direction????

Any suggestions where too look next?

[Anonymous]

I thought I heard (read) something about the difference between cast and forged pistons and rattling when they're cold. But you didn't mention having changed anything inside the motor? So that's probably no help.

[kz]

As far as I know, the engine is stock.

but.., the bike runs very well, is as fast as my GS1150 1984, we have tested, you know brothers....

The bike was also equipped with a four to one exhaust earlier...

Is it possible to check without dismounting the engine?

[Anonymous]

Does the rattle stop when you pull the clutch in? I read a while ago that the rattling is related to the clutch basket bouncing around. Mine does that same thing when it's cold, and when I'm waming it up i just leave it in neutral without pulling on the clutch lever. I'm not sure how serious a problem it is, but no burnouts from me until i can find a reinforced clutch basket , The sound does mostly go away once it's warmed up.

[kz]

Does the rattle stop when you pull the clutch in? I read a while ago that the rattling is related to the clutch basket bouncing around. Mine does that same thing when it's cold, and when I'm waming it up i just leave it in neutral without pulling on the clutch lever. I'm not sure how serious a problem it is, but no burnouts from me until i can find a reinforced clutch basket , The sound does mostly go away once it's warmed up.

I'm afraid the engaging/disengaging of the clutch has no influence of the rattle.

The clutch has been dismounted as the clutch plates where replaced, no difference after that, clutchbasket was inspected couldn't found anything wrong.

[Anonymous]

Mine also quiets down after warmup. Maybe it is being lubed better when the thing is warmer or a lot more oil has had a chance to be pumped up to the top end and quiet things down. Just guessing. My kawa eliminator sounded like it had marbles in the crank case till it warmed up. I have heard lots of folks with overhead cam bikes complain about the same thing. But what is the true answer??

[kz]

Dom,

The noise sounds like the cam-chain and the bike has been driven like that for at least 15 000 km.

The rattling sounds as the bike gives me a signal "please fix something before you ride me"

Then warm sounds the engine perfect, maybe some standard GS rattling but OK.

Do you belive the crank theory or do you think it is just to ride on and see if it increases?

[Anonymous]

sounds like pistons rattling to me

[Anonymous]

My pistons and bore are new in the last 10 thousand miles and i hope it s not pistons Rick. Ill go with the cam chain noise when cold but I will be the first to say i dont know and wish i did.

[Anonymous]

One other thing. a few mechanics say it is just typical engine noise and nothng is wrong

[Anonymous]

Mine growls like a bear when cold (I wouldn't call it a rattle). Quiet as a mouse when warm. I've always thought it the cam chain.

[Anonymous]

I have the same with my old girl. I originally thought cam chain but my mechanic assured it me wasn't. If it was cam chain then then rattle would be there regardless of engine temperature?

It's not clutch, nor valves, piston rattle is a possibility I guess but unlikely, significant oil usage would be the first sign of bore wear? Something I don't have a problem with.

I have been told several times it's nothing to worry about, which is kind of helpful.

[Anonymous]

Seems to be typical of over head camshaft rice burners

[Hap Call]

Mine also quiets down after warmup.

I see the same with my bike.

Hap

[Anonymous]

mine sounds the same hot or cold